字符串转换成指定的时间格式 + 实现日期加月操作

import java.text.ParseException;
import java.text.SimpleDateFormat;
import java.util.Calendar;
import java.util.Date;

public class Test {
  public static void main (String[] args) {

//格式化当前日期
		Date currentDate = java.sql.Date.valueOf(timeFormat.format(new Date()));
			try {
				Date d1 = addMonths(new Date(), 3);
				Date d2= new SimpleDateFormat("yyyy-MM-dd") .parse("2010-5-22 18:48:00");
				Date d3 =new SimpleDateFormat("yyyy-MM-dd") .parse("2007-8-11 ");
				SimpleDateFormat time=new SimpleDateFormat("yyyy-MM-dd");
				Date d4 = new Date();
				String  d1Str =  time.format(d1);
				String  d2Str =  time.format(d2);
				String  d3Str = time.format(d3);
				String  d4Str = time.format(d4);
				System.out.println(d1Str);
				System.out.println(d2Str);
				System.out.println(d3Str);
				System.out.println("d4 == "+d4+"  d4Str == "+d4Str);
				System.out.println(d1Str.compareTo(d2Str));
			} catch (ParseException e) {
				e.printStackTrace();
			}
  }
  public static Date addMonths(Date date, int amount) {
      return add(date, Calendar.MONTH, amount);
  }
  
  public static Date add(Date date, int calendarField, int amount) {
      if (date == null) {
          throw new IllegalArgumentException("The date must not be null");
      }
      Calendar c = Calendar.getInstance();
      c.setTime(date);
      c.add(calendarField, amount);
      return c.getTime();
  }
}